Conventional building systems such as flooring systems for the ground floor of modern domestic properties have tended to be manufactured out of wood or concrete. Both materials possess excellent thermal properties, but the sound proofing of concrete is far superior to that of conventional wooden floors. As it is not practical (or often cost effective) to construct the second or subsequent floor of domestic buildings with concrete, these subsequent floors are usually manufactured from wooden floor joists, floor boards and/or particle board sheets.
The lack of sound proofing afforded by such flooring materials means that there will always be a tendency to hear noise such as footsteps of an individual walking across this flooring and squeaking from relative movement of the flooring and support joists.
In an attempt to address the problem of noise travelling between floors, soundproof insulation can be installed in the gap between the ceiling and the flooring of the next level which are separated by wooden trusses or joists.
This has been successful to some degree and the design of such trusses also enable conduits or wiring to be positioned between floors. However, the installation of additional soundproofing material increases the time and cost of building construction.
New Zealand Patent No. 537801 discloses a system and method which combine timber or steel trusses with pre-manufactured concrete floor elements to create a modular flooring system for inter level floors in buildings. Such a system was developed to alleviate the problem of noise travelling between floors by utilising concrete in a cheap and convenient manner. As concrete has inherent insulation properties it eliminates the need for additional insulation material to be installed between the ceiling and the flooring of the next level.
However, it is difficult to connect the pre-manufactured concrete floor elements to the timber trusses when employing the system and method of New Zealand Patent No. 537801. That is because the concrete elements need to be bolted directly to the timber trusses following alignment of the corresponding apertures. This alignment process can be difficult and time consuming. Also following alignment and joining, an industrial epoxy resin is often applied to the join to give the join requisite bond and strength. This process is labour intensive and also increases the time and cost of manufacture. Furthermore, the use of concrete increases the overall weight of the finished product (given that the practical minimum thickness of the concrete floor elements is 80 mm to ensure adequate cover of the reinforcing steel).
Issues with the weight of standard concrete have been resolved to some extent by the development of lightweight formulations. However, the use of lightweight concrete is also limited due to its lack of ductility. While conventional concrete is hardly known for its ductility, the cracking and brittle nature of concrete is even more pronounced in lightweight concrete, because the lightweight aggregate is typically weaker than the cement matrix, and provides little resistance to crack propagation. For products produced from such lightweight concrete, the fracture energy is typically only a fraction of that of conventional concrete.
Accordingly, it would be advantageous to provide an improved building system and method which alleviates the foregoing disadvantages of noise travelling between floors of a building, the difficulty of connecting cementitious building elements to trusses and which is lightweight and easy to utilise yet which also has sufficient crack resistance and ductility.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.
Throughout this specification, the word “comprise”, or variations thereof such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.